Motor vehicles typically include active restraint systems such as over-the-shoulder safety belts. Such belts are generally attached to a vehicle door pillar at a position slightly above a passenger shoulder. As a passenger's height may vary considerably, it is sometimes desirable to provide a strategy for adjusting the vertical pillar position of the shoulder belt relative to the passenger. Adjustment of the shoulder belt height at the pillar position may offer optimal safety belt operation and ergonomics.
Several strategies developed to provide shoulder belt height adjustment involve the use of a slidable member that moves vertically relative to a guide rail mounted to the vehicle pillar. Examples of such strategies include U.S. Pat. No. 5,758,901 to Harenberg; U.S. Pat. No. 5,911,439 to Pleyer et al.; U.S. Pat. No. 5,941,566 to Holzapfel et al.; and U.S. Pat. No. 6,334,629 to Griesemer et. al., which are incorporated by reference herein. In the Griesemer patent, for example, an adjustment carriage (e.g., the slidable member) includes an arresting mechanism that selectively allows the carriage to engage openings formed in a guide rail. Each engagement opening provides a discrete locking adjustment location. As such, a plurality of discrete locking positions are provided, but the number of height adjustment positions is limited to the number of the openings.
Although such patents disclose strategies that may effectively provide shoulder belt height adjustment, they typically provide a relatively small number of adjustment positions. It is possible to increase the number of engagement openings, however, this may reduce the integrity of the parts and/or increase the complexity and cost of the belt assembly. Accordingly, it would be desirable to provide a larger number of shoulder belt adjustment positions without the need for numerous engagement openings.
Another shoulder belt height adjustment strategy that involves the use of a slidable member moveable within a guide rail includes U.S. Pat. No. 5,779,273 to Schmidt, which is incorporated by reference herein. In the Schmidt patent, an adjusting element (e.g., the slidable member) includes two rotatable gears providing movement relative to a guide rail. In the Schmidt and other patents (e.g., U.S. Pat. No. 5,758,901 to Harenberg and U.S. Pat. No. 5,941,566 to Holzapfel et al.), moveable parts (e.g., gears, levers, etc.) are provided as part of the shoulder belt height adjustment assembly. The use of such auxiliary moveable parts may increase the complexity, cost, and failure rate of the assembly. Accordingly, it would be desirable to provide a shoulder belt height adjustment strategy that does not use auxiliary moveable parts.
Therefore, it would be desirable to provide a shoulder belt height adjuster assembly and method of operation that overcomes the aforementioned and other disadvantages.